Method of making camera copy



Patented Apr. 21, 1953 METHOD OF MAKING CAMERA COPY "Maurice D. McIntosh, Cleveland Heights, Ohio, assignor to Louis S. Sanders, Shaker Heights,

, Ohio No Drawing. Application August V13, 1947,

Serial No. 768,500

, 4 Claims. 1

This invention relates, as indicated, to a medium for use in making camera copy, and to a method of preparing the same.

It has heretofore been proposed to apply to a thin, flexible, transparent base sheet, such, for example, as cellophane (regenerated cellulose sheeting), a photographically-invisible shading pattern or design, such, for example, as a Ben Day or half-tone pattern, which, upon chemical development thereof, becomes photographically visible or black, and can thus be used as shading or other accompaniment for a line or other drawing, in the preparation of camera copy. Ex-

amples of media prepared and used for such purposes are disclosed in U. S. Patents 2,009,586 and 2,301,900.

One of the principal drawbacks to the use of media of the aforesaid character is the fact that the pattern or design, in each case, whether applied to the transparent base'sheet by printing or in any other manner, does not penetrate into the base sheet, but remain on top of the sheet, that is to say, the. pattern or design is superficial. As a consequence, when the sheet is applied over a line drawing, and caused to adhere to the latter, as by burnishing or rubbing the sheet, the pattern or design is subjectto injury or damage, with the result that when it is subsequently chemically developed, it is not clear and distinct.

Another drawbackto the use of such media is the fact that it is not usuallygselfiadherentto the drawing or othersheet bearing the line or other drawing, so that it must be held; in place with Scotch tape or rubber cement, thu interfering with the proper and efficient use of the media. i

The present invention has at its primary object the provision of a transparent mediumof the 'character described, which completely overcomes the aforesaid disadvantages or drawbacks.

Another object of the invention is to provide a medium of the character described, in which the applied pattern or design is of such a character or nature or has properties such that it penetrates the base sheet to an extent such that it is no longer superficial, but yet is fixed immediately after it has been applied to the base sheet, so that it cannot migrate or become diffused in the base sheet or film, with passage of time. If the pattern, in such case, were permitted to migrate in the film, downwardly and laterally, to an undue extent, it would become blurred and would not make a sharp, clear pattern upon subsequent development.

A further object of the invention is to provide in water.

medium can be adhered to a drawing'without the use of extraneous adhesives, such as Scotch tape or rubber cement.

A still further object of the-inventionis to provide a medium of the character described, which can be. manufactured in commercially desirable quantities at relatively low .cost.

Other objectsand-advantages of the invention will become apparent in the course of the following description.

In preparing the medium of the presentinvention, I first take a-thin colorless or transparent film of a non-moistureproof regenerated cellulose sheeting, preferably the kind known as cellophane, and l in particular, I use a cellophane known as Du Pont 300 P. T., and then apply to such film, as by printing, a Ben Daypattern or similar regularly recurring design, this pattern comprising a composition consisting of parts of commercial sorbitol (Arlex--Atla Powder Company) and 20 parts of cobaltous chloride The cellophane is permeable to the solution of cobaltous chloride in sorbitol, and the printed pattern penetrates into and below the surface of the film. The pattern, being a solution, would normally continue to migrate in the film and become blurred, but at the point where it has just penetrated below the surface, of the film, it is precipitated or fixed by immersing the film in a 15% solution ofmorpholine (OCH2CH2NI-ICH2CH2) This treatment forms an insoluble precipitate of a very :stable cobalti-ammonium compound, prevents any further migration of the pattern into the filmfand firmly embeds it in the film, just below the surface of the film.

It is of primary importance that the printed pattern be below the surface of the film and not merely adhered superficially thereto, because, in use, the film will be burnished or rubbed, sometimes rather severely, to secure good adhesion of the film to the drawing. The pattern, if superficially present on the film, would, in such cases, be damaged, making the medium valueless. The pattern, as thus incorporated in the film, is photographically invisible or transparent.

After the pattern has been thus fixed, and the film dried, a thin coating of microcrystalline wax (Microwax Quaker State Refining Company) i applied to the side or surface of the film opposite to that to which the pattern was applied.

coating, is transparent and. actinic light transmitting, and will not obscureor add anything photographically to a line drawing.

In use, the medium will be adhered to a line drawing, and then, whereshading is required as an accompaniment to the line drawing, the pattern may be chemically developed, as by means of a developing solution, consisting of 5 parts of sodium sulphide (NazS) and 100 parts of distilled water. The film is permeable to the sodium sulphide solution, which penetrates quickly to the cobalti-ammonium compound comprising the pattern, changing the latter immediately to black cobaltous sulphide which has good non-actinic properties.

Although non-moistureproof cellophane seems to have the most desirable properties for the base material, other plastic film materials, such as cellulose acetate, cellulose nitrate, etc. may be employed as the basematerial, if coated with a thin film of gelatin. It is only necessary that the base be permeable to the printing compound, fixing solution and developing solution, yet be insoluble in all of these.

Compounds other than cobaltous chloride may be used in the printing compound. Among these are water-soluble copper, iron, nickel, lead and mercury compounds. In fact, any compound that can be carried into the base film by a suitable vehicle, subsequently made insoluble, substantially transparent and actinic, and then finally made non-actinic by application of a suitable developing compound, may be effectively used in the printing compound.

Moreover, it is possible to use other materials asthe printing vehicle, instead of sorbitol. Such hygroscopic water miscible compounds as glycerol, ethylene glycol and diethylene glycol are suitable for this purpose. 7

It is to beunderstood that various changes may .be made in the details of the method and medium without departing from the spirit and scope of the invention.

Having thus described my invention, I claim:

1. The method which consists in applying to a base sheet of cellophane a Ben Day pattern comprising a composition consisting of sorbitol and cobaltous chloride, to which said base sheet is permeable, and into which said pattern penetrates, and then subjecting the pattern to the action of morpholine, which converts the attern into an insoluble compound, whereby further penetration of the pattern is arrested.

2. The method which consists in applying to a base sheet of cellophane a Ben Day pattern comprising a composition consisting of a vehicle selected from the group consisting of sorbitol, glycerohethylene glycol and diethylene glycol, and a metal compound selected from the group consisting of cobaltous chloride and water soluble compounds of copper, iron, nickel, lead and mercury, to which said .base sheet is permeable, and into which said pattern penetrates, and then subjecting the pattern to the action of morpholine, which converts the pattern into an insoluble compound, whereby further penetration of the pattern is arrested.

3. The method which consists in applying to a base sheet selectedfrom the group consisting of cellulose acetate and cellulose nitrate, having a thin film of gelatin thereon, a Ben Day pattern comprising a composition consisting of a vehicle selected from the group consisting of sorbitol, glycerol, ethylene glycol and diethylene glycol, and a, metal compound selected from the group consisting of water soluble compounds of cobalt, copper, iron, nickel, lead and mercury, to which said base sheet is permeable, and into which said pattern penetrates, and then subjecting the pattern to the action of morpholine, which converts the pattern into an insoluble compound, whereby further penetration of the pattern is arrested.

4. The method which consists in applying to a flexible transparent base sheet a Ben Day pattern comprising sorbitol containing cobaltous chloride, to which said base sheet is permeable, and into which said pattern penetrates, and then subjecting the pattern to the action of morpholine, which converts the pattern into an insoluble compound, whereby further penetration of the pattern is arrested.

MAURICE D. MoINTOSI-I;

References Cited in the file or this patent 7 UNITED STATES PATENTS Number Name 7 Date r 1,055,189 Krayn Mar. 4, 1913 1,091,443 Ruth et al.- Mar. 24, 1914 1,905,061 Sax Apr. 25, 1933 2,021,816 Swaysland Nov. 19, 1935 2,121,042 Morgan June 21', 1938 2,226,554 Drew Dec. 31, 1940 2,251,752 Mitchell Aug. 5, 1941 OTHER REFERENCES 

1. THE METHOD WHICH CONSISTS IN APPLYING TO A BASE SHEET OF CELLOPHANE A BEN DAY PATTERN COMPRISING A COMPOSITION CONSISTING OF SORBITOL AND COBALTOUS CHLORIDE, TO WHICH SAID BASE SHEET IS PERMEABLE, AND INTO WHICH SAID PATTERN PENETRATES, AND THEN SUBJECTING THE PATTERN TO THE ACTION OF MORPHOLINE, WHICH CONVERTS THE PATTERN INTO AN INSOLUBLE COMPOUND, WHEREBY FURTHER PENETRATION OF THE PATTERN IS ARRESTED. 